The present invention is concerned with anti-viral agents, pharmaceutical compositions containing these agents and methods of treating warm-blooded animals suffering from viral diseases.
Viral infections are generally taught to be responsible for a number of diseases of various nature such as, for example, rabies, hepatitis, herpes, common cold, etc. . . . More particularly, the latt disease is widely spread throughout the world and is a major cause of sickness and absence from work. An agent capable of treating said disease would be a great benefit to mankind and certainly be of great economic importance.
Up until now no such agents are available and there exists no established chemotherapeutic agent against the said disease.
The present invention discloses the useful anti-viral properties of a number of pyridazine derivatives and their use in the treatment of viral diseases. Some of the pyridazinamines of the present invention are known in the art as intermediates for the synthesis of other useful compounds or as compounds having certain pharmacological properties. These compounds and a number of structurally closely related compounds can be found in the following references.
In J. Med. Chem. 24, 59-63 (1981) there are described a number of 1H-imidazolyl-pyridazines, while in European Patent Number 55,583, U.S. Pat. Nos. 4,110,450, 4,104,385 and 2,985,657 a number of piperazinyl, pyrrolidinyl and piperidinyl substituted pyridazines are described as intermediates. In European Patent Number 9,655 3-chloro-6-[4-(2-methoxyphenyl)-1-piperazinyl]pyridazine and 1-chloro-4-(4-hydroxypiperidino)phtalazine are also described as intermediates. Moreover a number of substituted 1-piperzinyl-pyridazines are described in J. Med. Chem. 6, 541-4 (1963), in ibid. 8, 104-107 (1965) and ibid. 15, 295-301 (1972) as compounds having adrenolytic, anti-histaminic or analgesic activity.
The compounds of the present invention differ from the cited prior-art compounds by the specific substitution on the pyridazine moiety and particularly by their useful anti-viral properties.